The present invention relates to continuous ambulatory peritoneal dialysis ("CAPD") and continuous cycling peritoneal dialysis (CCPD), more particularly, to a method and apparatus for "bagless" CAPDCCPD.
CAPD was first developed in the mid-1970's for the removal of toxins from the body of a patient while the patient is permitted to remain totally ambulatory. The process involves the infusion of a dialysate fluid under prescribed conditions into the peritoneal cavity of the patient. The dialysate fluid remains in the peritoneal cavity for an extended residence period, typically four to five hours. During the residence period, toxic solutes are transported across the peritoneum and into the dialysate fluid by the natural processes of diffusion and convection while the patient goes about his normal activities. After the prescribed residence period, the dialysate fluid, along with the toxins, are removed from the peritoneal cavity for disposal and a new or fresh supply of dialysate fluid is infused into the peritoneal cavity. Further general information concerning CAPD can be obtained by referring to U.S. Pat. No. 4,239,041 of Popovich et al., entitled, "Method for Continuous Ambulatory Peritoneal Dialysis," the disclosure of which is incorporated herein by reference.
In the past, various methods and apparatus have been employed for performing bagless CAPD. In one such method, shown in the aforementioned U.S. patent, a bottle or bag of dialysate fluid is initially suspended at a height greater than the height of the peritoneal cavity of the patient. A first length of flexible tubing extends between an opening in the lower portion of the dialysate fluid bag to one port of a "Y" connector. A second length of flexible tubing extends from a second port of the "Y" connector to a catheter which has been surgically implanted in the abdominal wall of the patient. A third length of tubing interconnects the third port of the "Y" connector and an empty collection bottle or bag. Flow control clamps are provided on each of the three sections of tubing.
In explaining CAPD methods, it is normal to begin with the portion of the CAPD cycle which involves the fluid residence or "dwell" period. Therefore, in operation of the prior art apparatus, once the dwell period has been completed, the first and third tubes are connected to the "Y" connector and the clamps are removed from the second and third tubes, permitting the dialysate fluid and the toxins to drain from the peritoneal cavity through the catheter, through the second tube, through the "Y" connector, through the third tube and into the collection bag which is positioned at a level below that of the catheter. Once the drainage has been completed, the clamps are reinstalled on the second and third tubes, the full collection bag is removed, emptied and reconnected to the distal end of the third tube. A new, full bag or bottle of fresh dialysate fluid is connected to the distal end of the first tube. The clamps on the first and second tubes are removed, thereby permitting fluid from the full dialysate bottle or bag to flow by gravity through the first tube, through the "Y" connector, through the second tube, through the catheter and into the peritoneal cavity. The clamps are then reapplied to both the first and second tubes and the first and third tubes are disconnected from the "Y" connector to provide freedom of movement to the user during the dwell period.
While the prior art method and apparatus for CAPD is generally adequate, there are disadvantages to the use of apparatus of this type in which the tubing is clamped to prevent fluid flow. It has been determined that in some cases the clamping of the tubing results in kinks or other damage to the tubing which could obstruct or otherwise impede the proper flow of the fluid either into or out of the peritoneal cavity. In addition, it has been found that on some occasions, patients inadvertently removed all three of the clamps at the same time, resulting in the improper flow of dialysate fluid and possible contamination. Moreover, with some patients, particularly patients with severe arthritis, it is difficult for the patient to actuate the clamps. The manual sequence of opening and closing multiple clamps is confusing to some users and could result in improper fluid flows.
The present invention provides an improved method and apparatus for bagless CAPD which employs a special three-way valve for directing the flow of dialysate fluid into and out of the peritoneal cavity. The apparatus of the present invention employes no clamps so that kinking or other damage to the interconnecting tubing is avoided. In addition, the three-way valve of the present invention is simple to operate and precludes inadvertent interconnection of the various tubes, thereby preventing undesired fluid flows and/or contamination.
The present invention is also adapted to be utilized with continuous cycling peritoneal dialysis (CCPD) by employing large-sized fluid containers.